Muhammad's intention in allying with the Jews

Upon the advent of Islam, Muhammad told his followers to face in the direction of Jerusalem while performing their twice-a-day prayer. This was to ally with the Jews of Medina. Later he revised this by telling the Muslims to face the shrine at Mecca. Why do you think Muhammad chose to ally with the Jews? Was he merely looking for a way to establish his young religion by allowing his followers to commit to more traditional rites?